1. Field of the Invention
The present invention is concerned with a measuring instrument for the profile of a piled charge of a blast furnace.
2. Description of the Prior Art
Distribution of gas flow in a blast furnace is one of the most important factors related to the stable operation of the blast furnace. The distribution of the gas flow is closely connected with the piling condition of the material and fuel charged in the furnace. Therefore, the piling condition of the charge (hereinafter called "profile of the charge") must be controlled to keep the distribution of gas flow under control. Therefore, many of the current blast furnaces are equipped with a charge distributer plate (movable armor) which changes the piling profile of the raw material and fuel when they are charged, to control the profile of the charge, and consequently the distribution of gas flow in the furnace.
Therefore it is necessary to measure the profile of the charges at any given time to control the distribution of gas flow. Various means of measuring the profile of the charge have been proposed, which are generally classified as either non-contacting systems adopting electromagnetic waves, ultrasonic waves, radioactive rays, etc., and contacting systems employing a plumb measuring device.
The present invention belongs to the latter group, a contacting system, of which the prior art structure is devised to run a wire rope through a guide pipe which moves horizontally to the radial direction in the furnace. A plumb is attached to the end of the wire rope and hangs down, and the contact of the plumb to the charge surface is detected by a detector installed outside of the furnace and the depth of charge surface from the guide pipe is thus measured. The guide pipe is moved in the radial direction to measure several points on the radial direction, to estimate the profile of the charge.
In the prior art as described above, the plumb is lifted to the position of the guide pipe while the pipe is being moved, so that the plumb will not swing with the movement of the guide pipe being relocated.
Therefore, the prior art method has the disadvantage of taking too-much time for the measuring operation due to the number of steps involved, such as lowering the plumb, detecting the contact, raising the plumb, and shifting the guide pipe. Because charges are usually sinking at a rate of about 10 cm/min., in the case of making measurements at several points to determine the complete profile, the time required from the first measurement to the last is too long, causing changes in the profile of the charge itself, resulting in a drawback of inability of making an accurate configuration measurement.